[WIP] Add `*.mli`

[gfngfn]

👀： https://github.com/ocaml-community/yojson/releases/tag/2.0.0

- File "src/library.mli", line 10, characters 9-20:
- 10 |     ?buf:Bi_outbuf.t -> ?len:int -> ?std:bool -> t -> string
-               ^^^^^^^^^^^
- Error: Unbound module Bi_outbuf
[ERROR] The compilation of satyrographos.dev failed at "dune build -p satyrographos -j 2".

#=== ERROR while compiling satyrographos.dev ==================================#
# context     2.1.3 | linux/x86_64 | ocaml-base-compiler.4.12.1 | pinned(git+file:///home/runner/work/satyrographos/satyrographos#HEAD#50b8f0e8)
# path        ~/work/satyrographos/satyrographos/_opam/.opam-switch/build/satyrographos.dev
# command     ~/.opam/opam-init/hooks/sandbox.sh build dune build -p satyrographos -j 2
# exit-code   1
# env-file    ~/.opam/log/satyrographos-13929-748dcd.env
# output-file ~/.opam/log/satyrographos-13929-748dcd.out

[gfngfn]

Memo:

• src/registry.ml is not used from any other modules
• src/repository.ml is used only by src/registry.ml
• src/store.ml is used only by src/{registry,repository}.ml